The mdx Mutation in the 129/Sv Background Results in a Milder Phenotype: Transcriptome Comparative Analysis Searching for the Protective Factors
The mdx Mutation in the 129/Sv Background Results in a Milder Phenotype: Transcriptome Comparative Analysis Searching for the Protective Factors
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DOI：
10.1371/journal.pone.0150748
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发表时间：
2016-03-08
期刊：
影响因子：
3.7
通讯作者：
Vainzof, Mariz
中科院分区：
文献类型：
--
作者：
Calyjur, Priscila Clara;Almeida, Camila de Freitas;Vainzof, Mariz
mdx小鼠是杜氏肌营养不良症（DMD）（一种进行性和破坏性肌肉疾病）的良好遗传和分子小鼠模型。然而，由于其温和的表型，该模型不适合用于测试新疗法。在这里，我们将mdx突变转移到129/Sv菌株中，目的是创建更严重的DMD模型。出乎意料的是，前三代mdx（129）的功能分析显示，与原始mdx（C57 BL）相比，表型逐渐改善，与较少的结缔组织替代和更多的再生相关。进行转录组比较分析，以确定是什么保护这种新模型免受营养不良的特征。mdx（C57 BL）的差异表达基因（DEG）是mdx（129）的三倍（分别为371和137 DEG）。然而，这两种模型都呈现出比低表达更多的过表达基因，表明营养不良和再生改变与基因的激活而不是抑制有关。在功能分类方面，两种mdx模型的DEG均以免疫系统基因为主。排除该类别，mdx（129）模型显示内/外途径和稳态类别的参与减少，细胞外基质酶活性类别的参与增加。spp 1基因的过度表达是mdx（129）株中最显著的DEG特异表达。这通过相对mRNA分析和骨桥蛋白定量来证实。蛋白质的66 kDa条带的量（代表基因的翻译后产物）在蛋白质印迹上高约4.8倍。Spp 1是一种已知的DMD预后生物标志物，我们的数据表明，其上调可以有益于表型。建模的表达参与mdx突变与良性过程中的DEG应测试作为一个可能的治疗目标的营养不良的过程。
The mdx mouse is a good genetic and molecular murine model for Duchenne Muscular Dystrophy (DMD), a progressive and devastating muscle disease. However, this model is inappropriate for testing new therapies due to its mild phenotype. Here, we transferred the mdx mutation to the 129/Sv strain with the aim to create a more severe model for DMD. Unexpectedly, functional analysis of the first three generations of mdx(129) showed a progressive amelioration of the phenotype, associated to less connective tissue replacement, and more regeneration than the original mdx(C57BL). Transcriptome comparative analysis was performed to identify what is protecting this new model from the dystrophic characteristics. The mdx(C57BL) presents three times more differentially expressed genes (DEGs) than the mdx(129) (371 and 137 DEGs respectively). However, both models present more overexpressed genes than underexpressed, indicating that the dystrophic and regenerative alterations are associated with the activation rather than repression of genes. As to functional categories, the DEGs of both mdx models showed a predominance of immune system genes. Excluding this category, the mdx(129) model showed a decreased participation of the endo/exocytic pathway and homeostasis categories, and an increased participation of the extracellular matrix enzymatic activity categories. Spp1 gene overexpression was the most significant DEG exclusively expressed in the mdx(129) strain. This was confirmed through relative mRNA analysis and osteopontin protein quantification. The amount of the 66 kDa band of the protein, representing the post-translational product of the gene, was about 4,8 times higher on western blotting. Spp1 is a known DMD prognostic biomarker, and our data indicate that its upregulation can benefit phenotype. Modeling the expression of the DEGs involved in the mdx mutation with a benign course should be tested as a possible therapeutic target for the dystrophic process.